In recent years, large-scale switching systems such as large-capacity routers are required corresponding to an increase in the capacity of communication networks. In such a case, limitation of capacity, due to the distance of electrical connections or sizes in the large-capacity connections between cabinets or inside a cabinet, is concerned. This is because higher-speed and higher-density electric signal wiring and delays in electric wiring stand as bottlenecks in realizing higher performance, although operating speed and integration scale have been improved along with the developments in the IC and LSI techniques. As a technique to solve this problem, an optical interconnection is drawing the attention. As a configuration of a small and low-cost signal input/output device using optical interconnection, it is effective that the signal processing is performed by a logic LSI and interfacing with the outside is performed by an optoelectronic hybrid integrated module.
This type of optoelectronic hybrid integrated module has been so configured as to combine a base material, on which an optical device and a driver IC are mounted, and a case to which a light extracting part such as a lens is provided. FIG. 9 shows a schematic side sectional view of a conventional optoelectronic hybrid integrated module.
As shown in FIG. 9, on a wiring substrate 98 in which interlayer wiring 96 and wiring patterns are formed on the top and the back surfaces, an optical device 91 for transmitting or receiving optical signals is fixed with a solder, and the optical device 91 and the wiring of the wiring substrate 98 are connected by a metal wire 97, and a driver IC 92 (an electric amplifier IC in the case of receiver) for adjusting the current amplitude of the optical device 91 is fixed in the same way and is electrically connected. Further, on a case 93 made of a material such as covar or the like, a light coupling means 94 such as a planar microlens is mounted. Then, by mounting the case 93 on the wiring substrate 98, light coupling between the optical device 91 and the outside is realized through the light coupling means 94.
In the conventional optoelectronic hybrid integrated module, however, the wiring substrate and the case, on which each component is mounted separately, are used. For example, the optical device is fixed and connected to the wiring substrate with a solder or by wire bonding, the driver IC is fixed and connected to the wiring substrate by soldering, and the lens is fixed to the case with an adhesive or the like. Then, finally they are assembled as a whole. This causes a problem of an increase in the number of components and processes, and an increase in the mounting cost.
Further, in drawing out the wiring, a wider margin of the wiring is required for wire-bonding the optical device, which causes a problem that high-density mounting of the components becomes difficult.
Further, in order to carry out electromagnetic shielding effectively, the case is preferably made of metal such as covar, which causes a problem of an increase in the cost.
Further, in extracting or taking in lights, since the lens and the optical device are mounted separately, dispersion of the distance between the lens and the optical device or their positions becomes large, which causes a problem of dispersion of the optical outputs themselves.
Further, when sealing is considered, since the module is divided into the case and the wiring substrate, it is required to inject a sealing material into the hollow portion of the divided package consisting of the two parts. Moreover, since the lens is fixed with an adhesive, hermetic sealing is also difficult.